Morphometric and Length-Weight Relationship of the Nile tilapia (Oreochromis niloticus (Linnaeus, 1758) from Head Panjnad, Punjab, Pakistan

Morphometric studies address the development, growth, variation, systematics and structure of the population of an organism. In the present study, samples of Oreochromis niloticus were collected from Head PanjnadAlipur, Punjab, Pakistan for the analysis of morphometric characteristics. Results showed that the wet weight of fish samples ranged from 4.33 to 9.45g, with a mean value of 7.08 ± 1.49g, while length ranged from 17.5 to 23.6cm, with a mean value of 20.72± 1.56. Correlations between log total length with a log of various morphological parameters, such as wet body weight, standard length, body girth, body depth, head length, pectoral fin length, anal fin length, dorsal fin length and caudal peduncle length were highly significant (P<0.001) and positively correlated. Moreover, the relationship between log total length and some other morphological parameters was found to be unique, such as log pelvic fin length was a significant positive correlation (P<0.01), log eye diameter showed a significant negative correlation (P<0.001), while a non-significant negative correlation was observed for condition factor. Furthermore, the log wet body weight showed a highly significant positive correlation (P<0.001) with standard length, body depth, head length, body girth, pectoral fin length, anal fin length and caudal peduncle length. The correlation among log wet body weight with log dorsal fin length and log eye diameter recorded a highly significant negative correlation (P<0.001). The correlation between log wet body weight and log pelvic fin length was significantly positive (P<0.01). The value of ‘b’ was 2.66 in a length-weight relationship, suggesting a negative allometric growth for O. niloticus and it is significantly lower than the ideal value (b=3.0). The present study provided useful information about the morphometric analysis of O. niloticus and the outcomes of the mathematical equation, with relationships of different morphometric relationships. These relationships have great importance in fish conservation.